The traditional calendar of the Chinese people came into use in the 14th century BCE. However, legend has it that it was invented by the Yellow Emperor 黃帝 in the third millennium BCE.
The traditional Chinese calendar is based on precise astronomical observations of the sun's longitude and the phases of the moon. Like the Hebrew calendar, the Chinese calendar too is based on both the moon and the sun. The sun is associated with seasonal cyclicality and the moon with the cyclicality of the months. The day of the month signals the phase of the moon. This means that the first day in the month is the dark phase of the moon, while the 15th day is a full moon. In a regular year there are 12 months (353, 354 or 355 days) and in an intercalary year there are 13 months (383, 384 or 385 days).
In order to define the course of the Chinese year, first the dates of the dark phase of the moon, which is the first day in the month, must be determined (in astronomical terms – the precise conjunction between the sun and moon). Then, the dates on which the longitude of the sun is a multiple of 30° have to be determined. The longitude of the sun in the spring equinox is 0°, in the summer solstice - 90°, in the autumn equinox - 180°, and in the winter solstice - 270°. These dates divide the year into the four seasons. In medieval China the year was divided into five seasons in order to create a parallel to the five colors and the five elements. The fifth season was a short one between summer and autumn.
Throughout history, the counting of the years began every time a new emperor came to power, but this custom stopped in 1911, following the fall of the last Imperial dynasty and the rise of the Chinese republic.
The years are arranged in major cycles of 60 (12X5) years, with each cycle divided further into twelve smaller cycles in which the years are designated by the names of the five elements (wood, fire, earth, metal and water). The 12 signs are: rat 鼠 , ox 牛 , tiger 虎 , hare 兔 , dragon龙 , snake 蛇, horse 马, sheep 羊 , monkey 侯, rooster 鸡 , dog狗 and pig 猪.
In China, the calendar as a material item was considered a sacred paper. For more than 2,000 years the government included a Ministry of Astronomy where astronomical observations were carried out, events like eclipses were calculated and astrological forecasts were made. Astrological testimonies that have survived testify to a calendar based on both the sun and the moon, and existing from as early as the 14th century BCE. According to the traditional Chinese calendar, the year begins in the second dark phase of the moon after the winter solstice.
The Gregorian calendar was first introduced to the Chinese by Jesuit missionaries in the 17th century. Gradually, the use of the Gregorian calendar became prevalent. However, the idea of dividing time into weeks was only accepted by the Chinese at large when the Gregorian calendar was officially implemented in China in the 20th century.
Each season has a flower in bloom associated with it. Plum blossom symbolizes the winter, peony - spring, lotus – summer, and chrysanthemum - winter. The rose is the flower of the entire year because it blooms the whole year round.